INPUT VOLTAGE DETECTION CIRCUIT WITH A PARAMETER SETTING FUNCTION APPLIED IN A POWER CONVERTER AND PARAMETER SETTING AND CIRCUIT PROTECTING METHOD THEREOF
A parameter setting and circuit protecting method applied in a power converter are disclosed. An input voltage of the power converter is detected to generate a first detecting signal related to the input voltage. The first detecting signal will be thence compared with a threshold so as to generate a protecting signal for protecting the power converter. When a parameter setting signal is triggered, a current is provided so as to make the first detecting signal to generate a variation, thereby setting a parameter in accordance with the variation.
The present invention is related generally to an input voltage detection circuit applied in a power converter and, more particularly, to an input voltage detection circuit with a parameter setting function and a parameter setting and circuit protecting method.
BACKGROUND OF THE INVENTIONIn an AC power system, the many protection functions need the information of the input voltage, such as the brown-in/out protection function.
In some applications, the AC power converter also needs a parameter setting function, such as a burst mode level setting or a frequency reduction point setting.
As shown by
Therefore, it is desired a circuit and a method utilizing a single pin to achieve the protecting function and the parameter setting function.
SUMMARY OF THE INVENTIONAn object of the present invention is to provide an input voltage detection circuit with a parameter setting function applied in a power converter and a parameter setting and circuit protecting method thereof.
Another object of the present invention is to provide a circuit and a method utilizing a single pin in the power converter to protect circuits and set parameters.
According to the present invention, an input voltage detection circuit with a parameter setting function applied in a power converter comprises a first detecting circuit, a protecting circuit, a current source, and a second detecting circuit. The first detecting circuit detects an input voltage of the power converter to generate a first detecting signal related to the input voltage. The protecting circuit generates a protecting signal according to the first detecting signal so as to protect the power converter. In time of setting the parameter, the current source provides a current to make the first detecting signal to generate a variation. The second detecting circuit acquires the variation in order to set the parameter.
According to the present invention, a parameter setting and circuit protecting method of the power converter comprises detecting an input voltage of the power converter to generate the first detecting signal related to the input voltage. Thence, a protecting signal is generated according to the first detecting signal so as to protect the power converter. In time of setting the parameter, the method of the present invention provides a current to make the first detecting signal to generate a variation, and detects the variation to set the parameter.
Since the present invention utilizes the first detecting signal to protect circuits and set parameters, it only needs one single pin to receive the first detecting signal so as to achieve circuit protect function and parameter setting function.
These and other objectives, features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following description of the preferred embodiments according to the present invention taken in conjunction with the accompanying drawings, in which:
Referring to
In time of setting parameters, a parameter setting signal TA is triggered to turn on the switch 28. Accordingly, the current I1 of the current source 26 flows through the second resistor R2 via the switch 28 and the pin BNO. At the same time, the first detecting signal Vd1 generates a variation ΔV=I1×R2. The second detecting circuit 30 includes a sample and hold circuit 32 and a subtractor 34. While the parameter setting signal TA is triggered, the sample and hold circuit 32 samples and holds the first detecting signal Vd1 so as to generate a second detecting signal Vd2 as shown by time t1 and the waveform 52 in
While the present invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope thereof as set forth in the appended claims.
Claims
1-17. (canceled)
18. An input voltage detection circuit with a parameter setting function applied in a power converter comprising:
- a first detecting circuit for detecting an input voltage of the power converter to generate a first detecting signal related to the input voltage;
- a protecting circuit connected to the first detecting circuit for generating a protecting signal according to the first detecting signal for protecting the power converter; and
- a parameter setting circuit connected to the first detecting circuit for setting a parameter according to the first detecting signal.
19. The input voltage detection circuit of claim 18, wherein the parameter setting circuit comprises:
- a current source connected to the first detecting circuit for providing a current when a parameter setting signal is triggered so as to make the first detecting signal to generate a variation; and
- a second detecting circuit connected to the first detecting circuit for acquiring the variation for setting the parameter when the parameter setting signal is triggered.
20. The input voltage detection circuit of claim 19, further comprising a counter connected to the second detecting circuit for counting the variation provided by the second detecting circuit so as to set the parameter.
21. The input voltage detection circuit of claim 18, wherein the protecting signal triggers a brown-in/out protection.
22. The input voltage detection circuit of claim 18, wherein the protecting circuit turns off the power converter when the first detecting signal is lower than a threshold for a preset time.
23. The input voltage detection circuit of claim 18, wherein the first detecting circuit comprises:
- a rectifying circuit connected to an input of the power converter for rectifying the input voltage so as to generate a rectified voltage;
- a first resistor connected between the rectifying circuit and a node; and
- a second resistor connected between the node and a ground;
- wherein, the first resistor and the second resistor divide the rectified voltage so as to generate the first detecting signal at the node.
24. The input voltage detection circuit of claim 23, wherein the first detecting circuit further comprises a third resistor connected between the node and an output of the first detecting circuit for determining the variation.
25. The input voltage detection circuit of claim 18, wherein the protecting circuit comprises:
- a comparator connected to the first detecting circuit for generating a comparing signal when the first detecting signal is lower than a threshold; and
- a counter connected to the comparator for generating the protecting signal when a duration of the comparing signal reaches a preset time so as to turn off the power converter.
26. The input voltage detection circuit of claim 19, further comprising a switch connected between the current source and the first detecting circuit and turned on when the parameter setting signal is triggered, so that the first detecting signal generates the variation in accordance with the current of the current source.
27. The input voltage detection circuit of claim 19, wherein the second detecting circuit comprises:
- a sample and hold circuit connected to the first detecting circuit for sampling and holding the first detecting signal when the parameter setting signal is triggered so as to generate a second detecting signal; and
- a subtractor connected to the sample and hold circuit and the first detecting circuit for subtracting the second detecting signal from the first detecting signal so as to result the variation.
28. A parameter setting circuit protecting method of a power converter comprising the steps of
- A. detecting an input voltage of the power converter so as to generate a first detecting signal related to the input voltage;
- B. generating a protecting signal according to the first detecting signal so as to protect the power converter; and
- C. setting a parameter according to the first detecting signal.
29. The parameter setting circuit protecting method of claim 28, wherein the step C comprises:
- C1. providing a current when a parameter setting signal is triggered so as to make the first detecting signal to generate a variation; and
- C2. detecting the variation when the parameter setting signal is triggered so as to set the parameter.
30. The parameter setting circuit protecting method of claim 29, wherein the step C2 comprises counting the variation so as to set the parameter.
31. The parameter setting circuit protecting method of claim 28, wherein the step B comprises generating the protecting signal so as to trigger a brown-in/out protection.
32. The parameter setting circuit protecting method of claim 28, wherein the step B comprises turning off the power converter when the first detecting signal is lower than a threshold for a preset time.
33. The parameter setting circuit protecting method of claim 28, wherein the step A comprises the steps of:
- rectifying the input voltage to generate a rectified voltage; and
- dividing the rectified voltage to generate the first detecting signal.
34. The parameter setting circuit protecting method of claim 29, further comprising controlling the variation so as to adjust the parameter.
35. The parameter setting circuit protecting method of claim 28, wherein the step B comprises:
- generating a comparing signal when the first detecting signal is lower than a threshold; and
- generating the protecting signal when a duration of the comparing signal achieves a preset time.
36. The parameter setting circuit protecting method of claim 29, wherein the step C2 comprises:
- sampling and holding the first detecting signal when the parameter setting signal is triggered so as to generate a second detecting signal; and
- subtracting the second detecting signal from the first detecting signal so as to result the variation.
Type: Application
Filed: Aug 10, 2015
Publication Date: Mar 10, 2016
Inventors: Hsin-Yi WU (Taipei City), Chien-Fu TANG (Hsinchu City), Isaac Y. CHEN (Jubei City, Hsinchu County)
Application Number: 14/822,382